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    <title>Document</title>
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<script>
    function Star(uname, age) {
        this.uname = uname;
        this.age = age;
    }

    var that;
    Star.prototype.sing = function () {
        console.log('我会唱歌');
        that = this;
    }
    var ldh = new Star('刘德华', 18);
    // 1. 在构造函数中,里面this指向的是对象实例 ldh
    ldh.sing();
    console.log(that === ldh);

    // 2.原型对象函数里面的this 指向的是 实例对象 ldh
</script>
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